Tapeworm found in moose lungs shows links to wild canids

John Holyoke | BDN

John Holyoke | BDN

A vial containing lungworms that were found in a Maine moose, as seen in September 2012.

February 20, 2013 12:47 pmUpdated: February 22, 2013 1:53 pm

AUGUSTA, Maine — A three-year study has determined that tapeworms found in Maine moose likely begin their life cycle in wild canids, including coyotes and foxes, before being transferred to moose, according to a Maine Department of Inland Fisheries and Wildlife press release.

The DIF&W has been collaborating with the University of Maine Animal Health Lab, in examining the presence of lungworms, or Dictyocaulus spp., in moose. Lungworms have been noted in moose that have been found dead in late winter with heavy winter tick loads and the combination of both parasites has been implicated as a cause of calf mortality, according to the release.

Late in 2012, students once again increased sampling intensity of moose lungs from harvested animals and found Echinococcus granulosus, or EG, cysts in some moose lungs. EG is a very small tapeworm that has a two-part life cycle; one in canids (coyotes, foxes and domestic dogs) and the second in moose.

There are several known genotypes of this tapeworm, and genetic testing of the Maine tapeworms found that this EG is the northern, or least pathogenic, form, according to the release. Although Echinococcus granulosuscan infect humans, the form that is known to do so most often is the sheep-dog genotype.

Finding the northern, wild-type form of EG in moose in Maine likely suggests that wild canids in Maine are infected and that possibly domestic dogs are infected as well, and that fact may allow for human exposure to this parasite. It is also very likely that people have coexisted with these tapeworms for years with no apparent problems, the DIF&W said.

The adult tapeworm lives in the intestines of the canid host, while the larval form lives in the lungs or liver of an infected moose. Humans may become infected by ingesting eggs of the parasite picked up by contact with canid feces.

In conjunction with the Maine Center for Disease Control and Prevention and University of Maine Animal Health Lab/Cooperative Extension, the Department recommends that people encountering dead wild animals be cautious.

The DIF&W advises wearing rubber or latex gloves when field dressing game and thoroughly cooking any wild game meat that will be consumed. The department also recommends protecting your pets through regular veterinarian visits and avoiding contact with dead wild animals.

The Department of Inland Fisheries and Wildlife website has additional recommendations on its website www.maine.gov/ifw.